Diffraction et spectrométrie des neutrons

The neutron is a neutral particle which, ignoring atoms' electronic patterns, interacts with their nuclei and magnetic moments. Neutron scattering is used to determine the static and dynamic structure of condensed matter, in much the same way as light and X-ray scattering and diffraction techniques. Measurement times are similar (from 10 min to 10 h). As neutron sources are difficult to access, this technique is reserved for experiments where it is indispensable, i.e., essentially :

• to locate the position of hydrogen atoms in space and time, especially in systems containing heavy atoms;

• when the contrast between the nuclei alone allows the experiment or when isotopic substitution is used as a labeling method;

• to determine the space-time structure of magnetic moments in a sample;

• to determine phonon or magnon dispersion curves;

• when the opacity of the sample does not allow it to be studied by light scattering, or when the experiment requires a sample thickness too great to use X-ray diffraction.